Printer unit for assembly with image reader unit

ABSTRACT

A printer unit is provided having a body with a media input assembly for supporting media to be printed, and securing means for releasable engagement with complementary securing means on an image reader unit, and a print engine with a printhead and a control system to control the operation of the printhead. The body is shaped for nesting with the image reader unit such that the securing means are positioned for releasable engagement with the complementary securing means.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. application Ser. No.11/592,996 filed on Nov. 6, 2006, now issued U.S. Pat. No. 7,513,615,which is a Continuation of U.S. application Ser. No. 11/014,721 filed onDec. 20, 2004, now issued U.S. Pat. No. 7,152,972, which is aContinuation-In-Part Application of U.S. application Ser. No. 10/760,254filed on Jan. 21, 2004, now issued U.S. Pat. No. 7,448,734. In theinterests of brevity, the disclosure of the parent application isincorporated in its entirety into the present specification by crossreference.

FIELD OF THE INVENTION

The present invention relates to a printer unit, and more particularlyto an inkjet printer unit provided in combination with an image readingunit to function as a multi-functional image processing unit.

CO-PENDING APPLICATIONS

The following applications have been filed by the Applicantsimultaneously with U.S. Pat. No. 7,152,972:

11/014,731 11/014,764 11/014,763 7,331,663 7,360,861 7,328,973 7,427,1217,407,262 7,303,252 7,249,822 11/014,762 7,311,382 7,360,860 7,364,2577,390,075 7,350,896 7,429,096 7,384,135 7,331,660 7,416,287 11/014,7377,322,684 7,322,685 7,311,381 7,270,405 7,303,268 11/014,735 7,399,0727,393,076 11/014,750 11/014,749 7,249,833 11/014,769 11/014,7297,331,661 11/014,733 7,300,140 7,357,492 7,357,493 11/014,766 7,380,9027,284,816 7,284,845 7,255,430 7,390,080 7,328,984 7,350,913 7,322,6717,380,910 7,431,424 11/014,716 11/014,732 7,347,534 7,306,320 7,377,63511/014,727 11/014,730

The disclosures of these co-pending applications are incorporated hereinby reference.

CROSS REFERENCES TO RELATED APPLICATIONS

The following patents or patent applications filed by the applicant orassignee of the present invention are hereby incorporated bycross-reference.

7,364,256 7,258,417 7,293,853 7,328,968 7,270,395 11/003,404 11/003,4197,334,864 7,255,419 7,284,819 7,229,148 7,258,416 7,273,263 7,270,3936,984,017 7,347,526 11/003,463 7,364,255 7,357,476 11/003,614 7,284,8207,341,328 7,246,875 7,322,669 6,623,101 6,406,129 6,505,916 6,457,8096,550,895 6,457,812 7,152,962 6,428,133 7,204,941 7,282,164 10/815,6287,278,727 7,417,141 10/913,374 7,367,665 7,138,391 7,153,956 7,423,14510/913,379 10/913,376 7,122,076 7,148,345 7,416,280 7,252,366 10/683,0647,360,865 7,275,811 10/884,889 10/922,890 7,334,874 7,393,083 10/922,88910/922,884 10/922,879 10/922,887 10/922,888 10/922,874 7,234,7957,401,884 7,328,975 7,293,855 7,410,250 7,401,900 10/922,878 7,410,2437,360,871 10/922,877 6,746,105 7,156,508 7,159,972 7,083,271 7,165,8347,080,894 7,201,469 7,090,336 7,156,489 7,413,283 10/760,246 7,083,2577,258,422 7,255,423 7,219,980 10/760,253 7,416,274 7,367,649 7,118,19210/760,194 7,322,672 7,077,505 7,198,354 7,077,504 10/760,189 7,198,3557,401,894 7,322,676 7,152,959 7,213,906 7,178,901 7,222,938 7,108,3537,104,629 7,246,886 7,128,400 7,108,355 6,991,322 7,287,836 7,118,19710/728,784 7,364,269 7,077,493 6,962,402 10/728,803 7,147,308 10/728,7797,118,198 7,168,790 7,172,270 7,229,155 6,830,318 7,195,342 7,175,26110/773,183 7,108,356 7,118,202 10/773,186 7,134,744 10/773,185 7,134,7437,182,439 7,210,768 10/773,187 7,134,745 7,156,484 7,118,201 7,111,9267,431,433 09/575,197 7,079,712 6,825,945 7,330,974 6,813,039 6,987,5067,038,797 6,980,318 6,816,274 7,102,772 7,350,236 6,681,045 6,728,0007,173,722 7,088,459 09/575,181 7,068,382 7,062,651 6,789,194 6,789,1916,644,642 6,502,614 6,622,999 6,669,385 6,549,935 6,987,573 6,727,9966,591,884 6,439,706 6,760,119 7,295,332 7,064,851 6,826,547 6,290,3496,428,155 6,785,016 6,831,682 6,741,871 6,927,871 6,980,306 6,965,4396,840,606 7,036,918 6,977,746 6,970,264 7,068,389 7,093,991 7,190,49110/901,154 10/932,044 10/962,412 7,177,054 7,364,282 10/965,73310/965,933 10/974,742 10/986,375 6,982,798 6,870,966 6,822,639 6,737,5917,055,739 7,233,320 6,830,196 6,832,717 6,957,768 7,170,499 7,106,8887,123,239 10/727,181 10/727,162 7,377,608 7,399,043 7,121,639 7,165,8247,152,942 10/727,157 7,181,572 7,096,137 7,302,592 7,278,034 7,188,28210/727,159 10/727,180 10/727,179 10/727,192 10/727,274 10/727,16410/727,161 10/727,198 10/727,158 10/754,536 10/754,938 10/727,16010/934,720 7,369,270 6,795,215 7,070,098 7,154,638 6,805,419 6,859,2896,977,751 6,398,332 6,394,573 6,622,923 6,747,760 6,921,144 10/884,8817,092,112 7,192,106 7,374,266 7,427,117 10/854,488 7,281,330 10/854,5037,328,956 10/854,509 7,188,928 7,093,989 7,377,609 10/854,495 10/854,49810/854,511 7,390,071 10/854,525 10/854,526 10/854,516 7,252,35310/854,515 7,267,417 10/854,505 10/854,493 7,275,805 7,314,26110/854,490 7,281,777 7,290,852 10/854,528 10/854,523 10/854,52710/854,524 10/854,520 10/854,514 10/854,519 10/854,513 10/854,49910/854,501 7,266,661 7,243,193 10/854,518 10/854,517 10/934,628

BACKGROUND OF THE INVENTION

Printer units have traditionally been employed to interface with one ormore associated computers to generate images based upon control datatransmitted from the associated computers. The image quality and speedof image generation can vary considerably from printer unit to printerunit and is greatly dependant upon the type of printer unit employed.Generally speaking, the high speed printer units producing highresolution images at full colour are more expensive than printer unitsthat produce single colour, black and white images at lower speeds. Inthis regard, the type of printer unit employed in a particular situationis generally selected upon consideration of the type of print images tobe undertaken by the printer as well as the cost of the particularprinter unit.

More recently, the roles of traditional printer units have been expandedto provide additional functions, particularly in an office environment.For example, many office printer units have been developed to provideconventional printing functions as well as providing functions normallyassociated with copier machines. In this regard, an image reading unitsuch as a document scanner is coupled with the printer unit to provide aprinter unit with typical copy functions. Such multi-functional unitshave become popular due to the fact that they can achieve tasks thatwere previously performed by two or more separate units, therebyreducing the costs associated with maintaining two or more separateunits and reducing the amount of space required to accommodate suchunits.

Unfortunately, such multifunctional units are typically rather dedicatedunits, and are generally targeted towards office use and as such are ofa size and modularity that is rather restricted. Such units are alsotypically expensive, in terms of conventional printer units, and as suchin order for such units to compete within the printer market, theprinting units and/or the image reading units employed are generally ofa lesser standard then competitively priced single units. Such atrade-off can typically result in a multifunctional unit operating atinferior printing speeds and print qualities. Further to this, typicalmulti-functional units do not readily provide a means for the variousparts of the system to be mountable to each other to enable theindividual parts of the multi-functional units to be separated or addedonto. In this regard, due to the lack of modularity in the design ofsuch multi-functional units it is not possible to purchase the printerunit and the image reading unit separately, such that a printer unit canbe readily transformed into a multi-functional unit upon mounting theprinter unit to an image reading unit.

SUMMARY OF THE INVENTION

In a first aspect the present invention provides an inkjet printer unitcomprising:

-   -   a media input assembly for supporting media for printing;    -   a print engine for printing an image on the media; and,    -   a media output assembly for collecting printed media, the media        output assembly having an image reading unit with a surface for        collecting the printed media; wherein,    -   the print engine is between the media input assembly and the        media output assembly such that in use the media output assembly        rests flat on a support surface and the media input assembly        extends upwardly from the print engine.

Optionally the media input assembly and the print engine are mounted onthe image reader, and the image reader is configured to support theprinter unit on a working surface.

Optionally the image reader extends outwardly from the print engine andthe printed media is collected on an upper surface of the image reader.

Optionally the print engine comprises a media exit mechanism forejecting said printed media from said print engine following printing.

Optionally the upper surface of the image reader is configured tocapture said ejected printed media and to present the printed media forcollection

Optionally the upper surface of the image reader comprises a stop memberwhich contacts with a leading edge of the ejected media to capture saidejected media on the upper surface of the image reader for collection.

Optionally the print engine comprises a pagewidth printhead having aplurality of ink ejection nozzles disposed thereon for ejecting ink ontoa surface of the media as the media is transported past the printhead.

Optionally the printhead is provided on a cartridge and the cartridge isremovable from the print engine.

Optionally the cartridge comprises at least one ink storage reservoirfor storing ink for printing by said printhead.

Optionally the print engine comprises a cradle and the cradle isconfigured to receive the cartridge.

Optionally the cradle comprises a media transport mechanism fortransporting said media from said media input assembly past saidprinthead for printing.

Optionally the cradle comprises a control system which controls theoperation of the printhead and the transport mechanism to facilitateprinting of said image on the media.

Optionally the control system also controls the operation of the imagereading unit.

In a second aspect the present invention provides an inkjet printer unitcomprising:

-   -   a media input assembly for supporting media for printing;    -   a print engine for printing an image on the media; and,    -   a media output assembly for collecting printed media, the media        output assembly having an image reading unit with a surface for        collecting the printed media; wherein,    -   the print engine has a pagewidth printhead.

Optionally the media input assembly and the print engine are mounted onthe image reader, and the image reader is configured to support theprinter unit on a working surface.

Optionally the image reader extends outwardly from the print engine andthe printed media is collected on an upper surface of the image reader.

Optionally the print engine comprises a media exit mechanism forejecting said printed media from said print engine following printing.

Optionally the upper surface of the image reader is configured tocapture said ejected printed media and to present the printed media forcollection

Optionally the upper surface of the image reader comprises a stop memberwhich contacts with a leading edge of the ejected media to capture saidejected media on the upper surface of the image reader for collection.

Optionally the print engine comprises a pagewidth printhead having aplurality of ink ejection nozzles disposed thereon for ejecting ink ontoa surface of the media as the media is transported past the printhead.

Optionally the printhead is provided on a cartridge and the cartridge isremovable from the print engine.

Optionally the cartridge comprises at least one ink storage reservoirfor storing ink for printing by said printhead.

Optionally the print engine comprises a cradle and the cradle isconfigured to receive the cartridge.

Optionally the cradle comprises a media transport mechanism fortransporting said media from said media input assembly past saidprinthead for printing.

Optionally the cradle comprises a control system which controls theoperation of the printhead and the transport mechanism to facilitateprinting of said image on the media.

Optionally the control system also controls the operation of the imagereading unit.

In a third aspect the present invention provides an inkjet printer unitfor use with an image reader, the printer unit comprising:

-   -   a body having a media input assembly for supporting media to be        printed, and securing means for releasable engagement with        complementary securing means on the image reader; and,    -   a print engine with a pagewidth printhead and a control system        to control the operation of the printhead; wherein,    -   the body is shaped for nesting with the image reader unit such        that the securing means are positioned for releasable engagement        with the complementary securing means.

Optionally the body has a base which is shaped to be received within aseat provided in the image reading unit.

Optionally the base of the body comprises a plurality of recess portionsadapted to receive a plurality of locating members provided on the seatof the image reading unit to removably secure the body to the imagereading unit.

Optionally the base of the body includes an electrical inlet forreceiving an electrical connector provided on the seat of the imagereading unit, such that when the body is secured to said image readingunit an electrical path is formed between the body and the image readingunit to enable data and power to be transferred therebetween.

Optionally the control system of the print engine controls the operationof the image reading unit and data is transferred between the controlsystem and the image reading unit via the electrical path.

Optionally the body comprises a power source which supplies operatingpower to the image reading unit via the electrical path.

Optionally the printhead is provided on a cartridge and the cartridge isremovable from the print engine.

Optionally the cartridge comprises at least one ink storage reservoirfor storing ink for printing by said printhead.

Optionally the print engine comprises a cradle and the cradle isconfigured to receive the cartridge.

Optionally the cradle comprises a media transport mechanism fortransporting said media from said media input assembly past saidprinthead for printing.

In a further aspect there is provided an image reader unit for use withan inkjet printer unit, the image reader unit comprising:

-   -   a media reading surface for receiving printed media from the        printer unit and presenting the printed media for reading; and    -   complementary securing means for releasable engagement with        securing means on the printer unit; wherein,    -   the image reader is shaped for nesting with the printer unit        such that the complementary securing means are positioned for        releasable engagement with the securing means.

In a further aspect there is provided an image processing apparatus forprinting an image onto a media surface and for reading and recordingimage information associated with an image on a media surface, theapparatus comprising:

-   -   an inkjet printer unit having a media input assembly for        supporting media to be printed;    -   a print engine with a pagewidth printhead and a control system        to control the operation of the printhead; and,    -   an image reading unit having a media reading surface for        receiving printed media from the printer unit and presenting the        printed media for reading; wherein,    -   the inkjet printer unit nestingly engages with, and is        releasably secured to, the image reader unit.

In a further aspect there is provided an image processing apparatus forprinting an image onto a media surface and for reading and recordingimage information associated with an image on a media surface, theapparatus comprising:

-   -   an inkjet printer unit having a media input assembly for        supporting media to be printed;    -   a print engine with a pagewidth printhead and a control system        to control the operation of the printhead; and,    -   an image reading unit having a media reading surface for        receiving printed media from the printer unit and presenting the        printed media for reading; wherein,    -   the inkjet printer unit nestingly engages with, and is        releasably secured to, the image reader unit.

In a further aspect there is provided an image processing apparatus forprinting an image onto a media surface and for reading image informationassociated with an image on a media surface, the apparatus comprising:

-   -   an inkjet printer unit having a media input assembly for        supporting media to be printed;    -   an image reading unit having an image reader and a media reading        surface for receiving printed media and presenting the printed        media for the image reader to read the image information; and,    -   a print engine with a pagewidth printhead and a control system        to control the operation of the printhead, the printhead having        a plurality of ink ejection nozzles for ejecting individual        drops of ink onto the media to be printed; wherein,    -   the control system determines whether each of the nozzles ejects        a drop of ink at a rate of at least 50 million determinations        per second.

In a further aspect there is provided an image reading unit, wherein thebody comprises a seat portion and the seat portion is shaped to receivethe inkjet printer unit therein.

In a further aspect there is provided an image reading unit, wherein thesecuring means is provided on the seat portion and comprises at leastone locating member extending from the seat portion and adapted toengage with a corresponding receiving member provided on the inkjetprinter unit.

In a further aspect there is provided an image reading unit, wherein thereceiving member is a recess and the locating member is shaped to bereceived within the recess.

In a further aspect there is provided an image reading unit, wherein anelectrical connector is provided on the seat portion to contact with acorresponding electrical connector provided on the inkjet printer unit,such that when the inkjet printer unit is received in said seat portionan electrical path is formed between the inkjet printer unit and theimage reader to enable data and power to be transferred therebetween.

In a further aspect there is provided an image reading unit, wherein theimage reader comprises a head portion and the head portion is arrangedto move along the surface of the media to collect the image informationassociated with the image formed on the surface of the media.

In a further aspect there is provided an image reading unit, wherein theimage information collected by the image reader is stored within acontroller provided with the image reader.

In a further aspect there is provided an image reading unit, wherein theimage information stored within the controller is sent to the inkjetprinter unit for processing via the electrical path.

In a further aspect there is provided an image reading unit, wherein thecontroller coordinates the operation of the image reading unit followingcontrol commands received from said inkjet printer unit.

In a further aspect there is provided an image processing apparatus forprinting an image onto a media surface and for reading image informationassociated with an image on a media surface, the apparatus comprising:

-   -   an inkjet printer unit having a media input assembly for        supporting media to be printed;    -   an image reading unit having an image reader and a media reading        surface for receiving printed media and presenting the printed        media for the image reader to read the image information; and,    -   a print engine with a pagewidth printhead and a control system        to control the operation of the printhead; wherein,    -   the printhead has at least 5000 ink ejection nozzles for        ejecting individual drops of ink onto the media.

In a further aspect there is provided an image reading unit, wherein thebody comprises a seat portion and the seat portion is shaped to receivethe inkjet printer unit therein.

In a further aspect there is provided an image reading unit, wherein thereceiving member is a recess and the locating member is shaped to bereceived within the recess.

In a further aspect there is provided an image reading unit, wherein anelectrical connector is provided on the seat portion to contact with acorresponding electrical connector provided on the inkjet printer unit,such that when the inkjet printer unit is received in said seat portionan electrical path is formed between the inkjet printer unit and theimage reader to enable data and power to be transferred therebetween.

In a further aspect there is provided an image reading unit, wherein theimage reader comprises a head portion and the head portion is arrangedto move along the surface of the media to collect the image informationassociated with the image formed on the surface of the media.

In a further aspect there is provided an image reading unit, wherein theimage information collected by the image reader is stored within acontroller provided with the image reader.

In a further aspect there is provided an image reading unit, wherein theimage information stored within the controller is sent to the inkjetprinter unit for processing via the electrical path.

In a further aspect there is provided an image reading unit, wherein thecontroller coordinates the operation of the image reading unit followingcontrol commands received from said inkjet printer unit.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a front perspective view of a multi-purpose imageprocessing apparatus in accordance with an embodiment of the presentinvention;

FIG. 2 shows a schematic of document data flow in a printing systemincorporating the printer unit of the present invention;

FIG. 3 shows a more detailed schematic showing an embodiment of thearchitecture used in the control system of the printer unit of thepresent invention;

FIG. 4 shows a block diagram showing an embodiment of the control systemused in the printer unit of the present invention;

FIG. 5 shows a front perspective view of the printer unit of the presentinvention;

FIG. 6 shows an exploded front perspective view of the printer unit ofFIG. 5;

FIG. 7 shows a rear perspective view of the printer unit of FIG. 5;

FIG. 8 shows a front plan view of the printer unit of FIG. 5;

FIG. 9 shows a right side plan view of the printer unit of FIG. 5;

FIG. 10 shows a left side plan view of the printer unit of FIG. 5;

FIG. 11 shows a bottom plan view of the printer unit of FIG. 5;

FIG. 12 shows a front perspective view of the printer unit of FIG. 5with the media output assembly extended and media loaded in the mediainput assembly;

FIG. 13 shows a front perspective view of the printer unit of FIG. 5with the cover of the printer unit open exposing the print engine;

FIG. 14 shows a sectional side view of the printer unit of FIG. 5;

FIGS. 15 a and 15 b show a front perspective view of the light sourceand the tube of the visual indicator unit respectively;

FIG. 16 shows a vertical sectional view of a single nozzle for ejectingink, for use with the invention, in a quiescent state;

FIG. 17 shows a vertical sectional view of the nozzle of FIG. 16 duringan initial actuation phase;

FIG. 18 shows a vertical sectional view of the nozzle of FIG. 17 laterin the actuation phase;

FIG. 19 shows a perspective partial vertical sectional view of thenozzle of FIG. 16, at the actuation state shown in FIG. 18;

FIG. 20 shows a perspective vertical section of the nozzle of FIG. 16,with ink omitted;

FIG. 21 shows a vertical sectional view of the of the nozzle of FIG. 20;

FIG. 22 shows a perspective partial vertical sectional view of thenozzle of FIG. 16, at the actuation state shown in FIG. 17;

FIG. 23 shows a plan view of the nozzle of FIG. 16;

FIG. 24 shows a plan view of the nozzle of FIG. 16 with the lever armand movable nozzle removed for clarity;

FIG. 25 shows a perspective vertical sectional view of a part of aprinthead chip incorporating a plurality of the nozzle arrangements ofthe type shown in FIG. 16;

FIG. 26 shows a schematic showing CMOS drive and control blocks for usewith the printer unit of the present invention;

FIG. 27 shows a schematic showing the relationship between nozzlecolumns and dot shift registers in the CMOS blocks of FIG. 26;

FIG. 28 shows a more detailed schematic showing a unit cell and itsrelationship to the nozzle columns and dot shift registers of FIG. 27;

FIG. 29 shows a circuit diagram showing logic for a single printernozzle suitable for use with the printer unit of the present invention;

FIG. 30 shows an exploded front perspective view of the image readingunit of the present invention;

FIG. 31 shows a bottom plan view of the multi-purpose image processingapparatus of FIG. 1;

FIG. 32 shows a left side plan view of the multi-purpose imageprocessing apparatus of FIG. 1;

FIG. 33 shows a sectional side plan view of the multi-purpose imageprocessing apparatus of FIG. 1;

FIG. 34 shows an enlarged sectional side plan view of the multi-purposeimage processing apparatus of FIG. 1;

FIG. 35 shows a front perspective view of the multi-purpose imageprocessing apparatus of FIG. 1 having the lid of the image reading unitfunctioning as media output assembly;

FIG. 36 shows a front perspective view of the multi-purpose imageprocessing apparatus of FIG. 1 with the lid of the image reading unit inan open position exposing the reading surface of the image reading unit.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As shown in FIG. 1, the present invention is embodied in a multi-purposeimage processing apparatus 1 that is capable of both reading an imagevia an image reading unit 701 and printing an image via an inkjetprinter unit 2. The image reading unit 701 may be in the form of atraditional flat bed scanner unit, and the apparatus 1 is configuredsuch that the image reading unit 701 and the inkjet printer unit 2 areable to perform their individual tasks both in combination and inisolation. In this regard, the apparatus 1 can function as an imagereading unit, an inkjet printer unit or as a copier unit whereby theimage reading unit and the inkjet printer unit functions combine toprint an image read by the image reading unit. The manner in which theapparatus is configured to provide such a multi-function system ofoperation will be described in more detail below.

As the image processing apparatus 1 of the present invention is made upof an inkjet printer unit 2 and an image reading unit 701, each of theseunits will firstly be described in isolation.

Inkjet Printer Unit

As shown schematically in FIG. 2, in use, the printer unit 2 is arrangedto print documents received from the scanning unit 95 or an externalsource, such as a computer system 102, onto a print media, such as asheet of paper. In this regard, the printer unit 2 includes means whichallow electrical connection between the unit 2 and the computer system102, the manner in which will be described later, to receive data whichhas been pre-processed by the computer system 102. In one form, theexternal computer system 102 is programmed to perform various stepsinvolved in printing a document, including receiving the document (step103), buffering it (step 104) and rasterizing it (step 106), and thencompressing it (step 108) for transmission to the printer unit 2.

According to one embodiment of the present invention, the printer unit 2may receive a document from the external computer system 102 in the formof a compressed, multi-layer page image, wherein control electronics 72provided within the printer unit 2 buffers the image (step 110), andthen expands the image (step 112) for further processing. The expandedcontone layer is dithered (step 114) and then the black layer from theexpansion step is composited over the dithered contone layer (step 116).Coded data may also be rendered (step 118) to form an additional layer,to be printed (if desired) using an infrared ink that is substantiallyinvisible to the human eye. The black, dithered contone and infraredlayers are combined (step 120) to form a page that is supplied to aprinthead for printing (step 122).

In this particular arrangement, the data associated with the document tobe printed is divided into a high-resolution bi-level mask layer fortext and line art and a medium-resolution contone color image layer forimages or background colors. Optionally, colored text can be supportedby the addition of a medium-to-high-resolution contone texture layer fortexturing text and line art with color data taken from an image or fromflat colors. The printing architecture generalises these contone layersby representing them in abstract “image” and “texture” layers which canrefer to either image data or flat color data. This division of datainto layers based on content follows the base mode Mixed Raster Content(MRC) mode as would be understood by a person skilled in the art. Likethe MRC base mode, the printing architecture makes compromises in somecases when data to be printed overlap. In particular, in one form alloverlaps are reduced to a 3-layer representation in a process (collisionresolution) embodying the compromises explicitly.

As mentioned previously, data is delivered to the printer unit 2 in theform of a compressed, multi-layer page image with the pre-processing ofthe image performed by a mainly software-based computer system 102. Inturn, the printer unit 2 processes this data using a mainlyhardware-based system as is shown in more detail in FIG. 3.

Upon receiving the data, a distributor 230 converts the data from aproprietary representation into a hardware-specific representation andensures that the data is sent to the correct hardware device whilstobserving any constraints or requirements on data transmission to thesedevices. The distributor 230 distributes the converted data to anappropriate one of a plurality of pipelines 232. The pipelines areidentical to each other, and in essence provide decompression, scalingand dot compositing functions to generate a set of printable dotoutputs.

Each pipeline 232 includes a buffer 234 for receiving the data. Acontone decompressor 236 decompresses the color contone planes, and amask decompressor decompresses the monotone (text) layer. Contone andmask scalers 240 and 242 scale the decompressed contone and mask planesrespectively, to take into account the size of the medium onto which thepage is to be printed.

The scaled contone planes are then dithered by ditherer 244. In oneform, a stochastic dispersed-dot dither is used. Unlike a clustered-dot(or amplitude-modulated) dither, a dispersed-dot (orfrequency-modulated) dither reproduces high spatial frequencies (i.e.image detail) almost to the limits of the dot resolution, whilesimultaneously reproducing lower spatial frequencies to their full colordepth, when spatially integrated by the eye. A stochastic dither matrixis carefully designed to be relatively free of objectionablelow-frequency patterns when tiled across the image. As such, its sizetypically exceeds the minimum size required to support a particularnumber of intensity levels (e.g. 16×16×8 bits for 257 intensity levels).

The dithered planes are then composited in a dot compositor 246 on adot-by-dot basis to provide dot data suitable for printing. This data isforwarded to data distribution and drive electronics 248, which in turndistributes the data to the correct nozzle actuators 250, which in turncause ink to be ejected from the correct nozzles 252 at the correct timein a manner which will be described in more detail later in thedescription.

As will be appreciated, the components employed within the printer unit2 to process the image for printing depend greatly upon the manner inwhich data is presented. In this regard it may be possible for theprinter unit 2 to employ additional software and/or hardware componentsto perform more processing within the printer unit 2 thus reducing thereliance upon the computer system 102. Alternatively, the printer unit 2may employ fewer software and/or hardware components to perform lessprocessing thus relying upon the computer system 102 to process theimage to a higher degree before transmitting the data to the printerunit 2.

In all situations, the components necessary to perform the abovementioned tasks are provided within the control electronics 72 of theprinter unit 2, and FIG. 4 provides a block representation of anembodiment of such electronics.

In this arrangement, the hardware pipelines 232 are embodied in a SmallOffice Home Office Printer Engine Chip (SoPEC). As shown, a SoPEC deviceconsists of 3 distinct subsystems: a Central Processing Unit (CPU)subsystem 301, a Dynamic Random Access Memory (DRAM) subsystem 302 and aPrint Engine Pipeline (PEP) subsystem 303.

The CPU subsystem 301 includes a CPU 30 that controls and configures allaspects of the other subsystems. It provides general support forinterfacing and synchronizing all elements of the printer unit 2, aswill be described later. It also controls the low-speed communication toQA chips (which are described below). The CPU subsystem 301 alsocontains various peripherals to aid the CPU, such as General PurposeInput Output (GPIO, which includes motor control), an InterruptController Unit (ICU), LSS Master and general timers. The SerialCommunications Block (SCB) on the CPU subsystem provides a full speedUSB 1.1 interface to the host as well as an Inter SoPEC Interface (ISI)to other SoPEC devices (not shown).

The DRAM subsystem 302 accepts requests from the CPU, SerialCommunications Block (SCB) and blocks within the PEP subsystem. The DRAMsubsystem 302, and in particular the DRAM Interface Unit (DIU),arbitrates the various requests and determines which request should winaccess to the DRAM. The DIU arbitrates based on configured parameters,to allow sufficient access to DRAM for all requesters. The DIU alsohides the implementation specifics of the DRAM such as page size, numberof banks and refresh rates.

The Print Engine Pipeline (PEP) subsystem 303 accepts compressed pagesfrom DRAM and renders them to bi-level dots for a given print linedestined for a printhead interface (PHI) that communicates directly withthe printhead. The first stage of the page expansion pipeline is theContone Decoder Unit (CDU), Lossless Bi-level Decoder (LBD) and, whererequired, Tag Encoder (TE). The CDU expands the JPEG-compressed contone(typically CMYK) layers, the LBD expands the compressed bi-level layer(typically K), and the TE encodes any Netpage tags for later rendering(typically in IR or K ink), in the event that the printer unit 2 hasNetpage capabilities. The output from the first stage is a set ofbuffers: the Contone FIFO unit (CFU), the Spot FIFO Unit (SFU), and theTag FIFO Unit (TFU). The CFU and SFU buffers are implemented in DRAM.

The second stage is the Halftone Compositor Unit (HCU), which dithersthe contone layer and composites position tags and the bi-level spotlayer over the resulting bi-level dithered layer.

A number of compositing options can be implemented, depending upon theprinthead with which the SoPEC device is used. Up to 6 channels ofbi-level data are produced from this stage, although not all channelsmay be present on the printhead. For example, the printhead may be CMYonly, with K pushed into the CMY channels and IR ignored. Alternatively,any encoded tags may be printed in K if IR ink is not available (or fortesting purposes).

In the third stage, a Dead Nozzle Compensator (DNC) compensates for deadnozzles in the printhead by color redundancy and error diffusing of deadnozzle data into surrounding dots.

The resultant bi-level 6 channel dot-data (typically CMYK, Infrared,Fixative) is buffered and written to a set of line buffers stored inDRAM via a Dotline Writer Unit (DWU).

Finally, the dot-data is loaded back from DRAM, and passed to theprinthead interface via a dot FIFO. The dot FIFO accepts data from aLine Loader Unit (LLU) at the system clock rate (pclk), while thePrintHead Interface (PHI) removes data from the FIFO and sends it to theprinthead at a rate of ⅔ times the system clock rate.

In the preferred form, the DRAM is 2.5 Mbytes in size, of which about 2Mbytes are available for compressed page store data. A compressed pageis received in two or more bands, with a number of bands stored inmemory. As a band of the page is consumed by the PEP subsystem 303 forprinting, a new band can be downloaded. The new band may be for thecurrent page or the next page.

Using banding it is possible to begin printing a page before thecomplete compressed page is downloaded, but care must be taken to ensurethat data is always available for printing or a buffer under-run mayoccur.

The embedded USB 1.1 device accepts compressed page data and controlcommands from the host PC, and facilitates the data transfer to eitherthe DRAM (or to another SoPEC device in multi-SoPEC systems, asdescribed below).

Multiple SoPEC devices can be used in alternative embodiments, and canperform different functions depending upon the particularimplementation. For example, in some cases a SoPEC device can be usedsimply for its onboard DRAM, while another SoPEC device attends to thevarious decompression and formatting functions described above. This canreduce the chance of buffer under-run, which can happen in the eventthat the printer commences printing a page prior to all the data forthat page being received and the rest of the data is not received intime. Adding an extra SoPEC device for its memory buffering capabilitiesdoubles the amount of data that can be buffered, even if none of theother capabilities of the additional chip are utilized.

Each SoPEC system can have several quality assurance (QA) devicesdesigned to cooperate with each other to ensure the quality of theprinter mechanics, the quality of the ink supply so the printheadnozzles will not be damaged during prints, and the quality of thesoftware to ensure printheads and mechanics are not damaged.

Normally, each printing SoPEC will have an associated printer QA, whichstores information printer attributes such as maximum print speed. Anink cartridge for use with the system will also contain an ink QA chip,which stores cartridge information such as the amount of ink remaining.The printhead also has a QA chip, configured to act as a ROM(effectively as an EEPROM) that stores printhead-specific informationsuch as dead nozzle mapping and printhead characteristics. The CPU inthe SoPEC device can optionally load and run program code from a QA Chipthat effectively acts as a serial EEPROM. Finally, the CPU in the SoPECdevice runs a logical QA chip (ie, a software QA chip).

Usually, all QA chips in the system are physically identical, with onlythe contents of flash memory differentiating one from the other.

Each SoPEC device has two LSS system buses that can communicate with QAdevices for system authentication and ink usage accounting. A largenumber of QA devices can be used per bus and their position in thesystem is unrestricted with the exception that printer QA and ink QAdevices should be on separate LSS busses.

In use, the logical QA communicates with the ink QA to determineremaining ink. The reply from the ink QA is authenticated with referenceto the printer QA. The verification from the printer QA is itselfauthenticated by the logical QA, thereby indirectly adding an additionalauthentication level to the reply from the ink QA.

Data passed between the QA chips, other than the printhead QA, isauthenticated by way of digital signatures. In the preferred embodiment,HMAC-SHA1 authentication is used for data, and RSA is used for programcode, although other schemes could be used instead.

As will be appreciated, the SoPEC device therefore controls the overalloperation of the printer unit 2 and performs essential data processingtasks as well as synchronising and controlling the operation of theindividual components of the printer unit 2 to facilitate print mediahandling. In the remainder of the description the term controlelectronics 72 will be used to refer to the SoPEC device and any otherelectronics which are employed within the printer unit 2 to control itsoperation.

Whilst the printer unit 2 is intended to be incorporated with a scannerunit 95 to form the image processing apparatus 1 of the presentinvention, for reasons of clarity the structure and operation of theprinter unit 2 will be described with regard to its functionality as astand-alone unit.

FIGS. 5-15 depict the inkjet printer unit 2 which generally comprises amain body 3, a media input assembly 4 for retaining and supporting printmedia for printing, and a media output assembly 5 for collecting theprint media following printing.

As shown more clearly in FIG. 6, the structure of the main body 3 isformed by an upper frame unit 7 which is shaped to be received on alower frame unit 6. The upper and lower frame units 7, 6 together definea base 8, a rear 9 and an opening 10 upon which a cover 11 is received.The opening 10 provides access to an internal cavity 12 which containsthe print engine 70 and associated componentry.

As shown in FIG. 11, the base 8 is formed on the underside of the lowerframe unit 6 and has a lower surface 13 that supports the printer unit 2when the printer unit is used as a stand alone unit and positioned on asubstantially horizontal surface, such as a surface of a desk in a homeor office environment. In this arrangement, one or more foot supports 14extend from the lower surface 13 to provide additional stability to theprinter unit. The foot supports 14 are made from a friction inducingmaterial such as rubber, to increase the frictional contact between theprinter unit and the support surface. The manner in which the base 8 isconfigured to receive an image reading unit 701 will be described inmore detail later in the description.

As shown in FIG. 7, the rear 9 of the main body 3 is defined by the rearsurface of the lower frame unit 6 and the upper frame unit 7. A powersupply unit 15 is arranged to fit within a shaped recess in the lowerframe unit 6, to be located adjacent the rear 9 of the main body 3. Inone form, the power supply unit 15 is a fixed unit capable of receivingpower via power connector socket 16 from an external power supply andsupplying it to the various components of the unit. In another form, thepower supply unit 15 may be of a rechargeable type capable of storingpower for supply to the printer unit 2, and as such the unit 15 may beremovable from the frame unit 6 for replacement where necessary. Dataconnector sockets 17 are also formed in the lower frame unit 6 andprovide a means for connecting the printer unit 2 to an external source,such as a computer system 102, to provide data and commands to theprinter unit 2 in the manner as previously described. The data connectorsockets 17 are in the form of standard ethernet and USB Device socketswhich enable the printer unit 2 to be connected to the computer terminal102 or a network of computer terminals to receive data and commandstherefrom. Such information may also be received by the printer unit 2in a wireless manner by using a WIFI card 18 and/or a Bluetooth® card 19provided under a cover plate 20 on the rear surface of the upper frameunit 7. In each of these arrangements, all data received is transmittedfrom the sockets 17 and cards 18, 19 to the control system of theprinter unit 2 for processing and printing.

As is shown in FIGS. 5, 6, 8-10 and 13, the cover 11 of the main body 3comprises a lid 21 hingedly connected to the upper frame unit 7. The lid21 has a curved top surface 22 and an angled front surface 23 and twoend surfaces 24 which are shaped to mate with the upper edge of theupper frame unit 7. The lid 21 is pivotally connected along a rear edgeof the top surface 22 with the upper frame unit 7. This pivotalconnection allows the lid 21 to be pivoted backwards to provide accessto the internal cavity 12 of the main body 3.

The angled front surface 23 has a recess 25 formed therein. The recess25 receives a user interface unit 26 that enables communication betweena user and the printer unit 2. The user interface unit 26 is an LCDtouch screen that conveys information to the user and allows the user todirectly input information to the printer unit 2 via selecting an optionon the display screen. The type of information which the user interfaceunit 26 may display to the user and which the user may input into theprinter unit can vary, however typically this can relate to the statusof the ink stored in the printer unit 2, the need to correct any paperjams or the like, as well as information relating to the ink refillingprocedure. The use of a touch screen LCD is particularly beneficial as auser interface, as the display can be programmed to a specific languagethereby overcoming the need to provide separate markings or text on theprinter unit 2 which may be specific to the country to which the printerunit is to be used. However, it should be appreciated that the userinterface unit 26 could be in a number of different forms, such asconventional buttons and the like, which allow the user to interact withthe printer unit 2.

The angled front surface 23 of the lid 21 is also provided with a visualindicator unit 27 which provides the user with a visual indication ofthe status of the printer. The visual indicator unit 27 extends alongthe surface of the lid 21 and is in the form of an elongated tube orpanel 28 which emits light from a light source 29. The colour and/orintensity of the light emitted from the visual indicator unit 27 can becontrolled in a manner that provides the user with an instant indicationof the state of the printer unit 2 without the need to refer to the userinterface unit 26.

The construction of the visual indicator unit 27 is shown in FIGS. 15 aand 15 b. As shown, the unit 27 consists of a light source 29 and anelongate panel 28. The light source 29 is in the form of three lightemitting diodes (LEDs) 30 arranged upon the surface of a printed circuitboard (PCB) 31. The LEDs 30 are red, green and blue LEDs which allow awide spectrum of light to be emitted from the panel 28. However it willbe appreciated that a single LED or other colored LEDs could also beemployed to perform a similar function. The PCB 31 may be the same PCBthat contains the control electronics 72 for the printer unit 2 or maybe a separate PCB that includes appropriate electronics to operate theLEDs 30 under control of the control electronics 72. The elongate panel28 is made from a material that allows light from the LEDs 30 to travelalong its length and to be transmitted from the surface of the panel.The panel 28 may be in the form of a hollow tube or pipe that is placedover the LEDs 30 to collect light emitted therefrom. The internalsurface of the tube or pipe may be coated with a film that enables aportion of the light to be reflected along the length of the panel 28,and a portion of light to pass from the panel 28 thereby illuminatingthe panel 28 which can be readily seen by the user along the surface ofthe panel 28.

In use, each of the LEDs 30 can be controlled to emit a light from thepanel 28 representative of the state of the printer unit 2. For example,to indicate to the user that the printer unit is in a standby mode ablue LED may be activated such that the panel 28 emits a blue light.During printing a green LED may be activated to emit a green light fromthe panel 28 and in the event of a problem such as a paper jam or aprinter error, a red LED may be activated to emit a red light from thepanel 28. Additionally, in order to create a decorative effect, each ofthe LEDs may be actuated in various combinations to emit a variety ofcoloured lights across a wide spectrum. As the light is emitted over alarge surface area, rather then merely at a point source as is the casewith a single LED provided on a printer unit, the user is more likely tovisually detect the state of the printer and to attend to the printerwhere necessary. Such a system performs an important function inensuring an efficient workplace and also provides a printer unit whichis aesthetically pleasing.

To supply print media to the printer unit 2 for printing, the mediainput assembly 4 extends from the rear 9 of the printer unit 2. Themedia input assembly 4 consists of a tray portion 32 and a media supportflap 33 which together form a surface for receiving one or more sheetsof print media 34 for printing by the printer unit 2. The media inputassembly 4 extends in a vertical direction from the main body 3 and isangled such that in use, the sheets of print media 34 are supported bythe media input assembly 4 in a vertical orientation and are drawn intothe printer via a downward path, as is shown in FIG. 14 and discussed inmore detail later.

As shown more clearly in FIG. 6, the tray portion 32 of the media inputassembly 4 is formed integrally with the upper frame unit 7, and as suchthe rear surface of the tray portion 32 forms part of the rear 9 of themain body 3. The tray portion 32 generally forms a receptacle forreceiving the print media 34 and includes a working surface 35 uponwhich the media 34 is placed, and a media support surface 36 at one endthereof adapted to receive an edge of the media 34 to maintain the media34 in an upright position. The tray portion 32 also includes a pair ofparallel extending side walls 37, 38 which define the maximum width ofthe print media that can be accommodated by the printer unit 2.

As is shown more clearly in FIG. 14, the media support surface 36 isdisposed at an obtuse angle to the working surface 35 of the trayportion 32, to aid in the delivery of a sheet of print media 34 from thetray portion 32 to the print engine 70 for printing. The working surface35 has an idler roller 39 incorporated therein to act with a pickermechanism 60 to facilitate the delivery of a sheet of print media 34from the working surface 35 to the print engine 70 for printing.Disposed at intervals along the media support surface 36 are a number ofraised strips 40 which extend from the media support surface 36 andsupport the leading edge of the media 34 above the surface 36. Thestrips 40 act to allow the leading edge of the media 34 to slide alongthe surface of the strips 40 under action of the picker mechanism 60 tofacilitate delivery of the media 34 from the tray portion 32. A pad 41is provided on the surface of the strip 40 adjacent the picker mechanism60 to provide a friction surface to facilitate separation of the uppermost sheet of media 10 when a plurality of sheets are supported upon theworking surface 35 of the tray portion 32. The pad 41 may be in the formof a rubber, felt or cork type material.

A margin slider 42 is adapted to be fitted over the working surface 35of the tray portion 32 via an integral hook element 43. A grooved recess(not shown) may be provided in the working surface 35 to receive alocating lug (not shown) of the slider 42 to maintain the slider 42 inengagement with the working surface 35. Such an arrangement allows theslider 42 to be moved in a controlled manner across the surface 35 toaccommodate print media 34 of varying widths. The margin slider 42extends the height of the tray portion 32 and is provided with a wallportion 45 that extends out from the working surface 35 of the trayportion 32 to abut against a side edge of the print media 34. Thisarrangement ensures that the print media 34 is properly aligned withinthe tray portion 32 to ensure controlled delivery of the sheets of mediato the print engine 70.

As shown in FIG. 6, the side walls 37, 38 of the tray portion 32 areprovided with locating lugs 46 on the inner surfaces thereof to enablethe media support flap 33 to be connected to the tray portion 32. Inthis regard, the media support flap 33 includes a pair of recessed tabs47 extending from an end thereof that receives the lugs 46 therebysecuring the media support flap 33 to the upper end of tray portion 32.With this arrangement, the media support flap 33 can pivot about thedistal end of the tray portion 32 such that the flap 33 can be moved toan extended position to support print media 34 loaded onto the mediainput assembly 4 (as shown in FIG. 5), or into a retracted position forpackaging or shipment, wherein the media support flap 33 is received ontop of the tray portion 32 (not shown).

The media support flap 33 extends beyond the distal end of the trayportion 32 to support print media 34 having a length greater than thelength of the tray portion 32. This arrangement ensures that the printmedia 34 is maintained in a substantially upright position, as shown inFIG. 12. In this regard, the surface of the media support flap 33 isprovided with a plurality of equispaced fin elements 48 that extendinglongitudinally along the surface of the flap 33. Each of the finelements 48 extend from the surface of the media support flap 35 anequal amount to thereby present a flat surface to the print media 34which is continuous with the working surface 35 of the tray portion 32.It is envisaged that the inner surface of the media support flap 33could also be a continuous moulded surface with appropriate slots formedin edge regions thereof to accommodate the side walls 37, 38 of the trayportion 32, when the media support flap 33 is folded for packaging ortransport of the printer unit 2.

As a stand-alone unit, the printer unit 2 is adapted to collect printedmedia via the media output assembly 5, as shown in FIG. 12. In thisarrangement, the media output assembly 5 is positioned in the base 8 ofthe main body 3 at the front of the printer unit 2. The media outputassembly 5 consists of a tray housing 50 and two extendible outputtrays, an upper output tray 51 and a lower output tray 52, both of whichare retained within the tray housing 50 when not in an extendedposition.

As shown in FIGS. 6 and 11, the tray housing 50 is removably receivedwithin a recess in the lower frame unit 6, and extends from the rear tomarginally beyond the front of the printer unit 2. The tray housing 50has an upper surface 53 and two side walls 54, 55 extending downwardlyfrom the upper surface 53. The front edge of the upper surface 53 isopen and has a recessed portion 56 formed therein to enable access tothe upper and lower output trays 51, 52 retained within the tray housing50.

The upper output tray 51 is shaped to be received and retained withinthe tray housing 50 by the two side walls 54, 55. The two side walls 54,55 have grooves (not shown) provided therein that extend the length ofthe tray housing 50. The upper output tray 51 is sized to be receivedwithin the grooves such that its longitudinal edges travel within thegrooves to allow the tray 51 to move relative to the tray housing 50.The grooves and the longitudinal edges of the upper output tray 51 arearranged such that the tray 51 is extendible from the tray housing 50,but is not removable from the tray housing 50. In this arrangement thetray 51 when in its retracted position, fits entirely within the trayhousing 50.

The lower output tray 52 is constructed in a similar manner to the upperoutput tray 51. However in this arrangement, the lower output tray 52 isreceived within two grooves provided in the longitudinal edges of theupper output tray 51. As is shown in FIG. 9, the lower output tray 52has a reduced width and thickness than the upper output tray 51 to allowthe lower tray 52 to travel within the upper tray. The lower output tray52 is arranged to fit entirely within the upper output tray 51 in aretracted state and the upper output tray 51 is also provided with arecessed portion 57 along its front edge thereof to enable access to astop member 58 provided on the front edge of the lower output tray 52.The lower output tray 52 and the upper output tray 51 may also beconfigured in a manner which allows the lower tray 52 to be extendedfrom the upper tray 51 but prevented from being removed from the uppertray, in a similar manner as described above. Other arrangements of thetrays which permit retraction and extension are also possible and wouldbe considered to fall within the scope of the present invention.

Prior to use, the media output assembly 5 is in a retracted state asshown in FIG. 5. The media output assembly 5 is brought into anoperational position, as shown in FIG. 12, when a user grips the stopmember 58 and extends the lower output tray 52. This action causes theentire media output assembly 5 to extend from the tray housing 50 tocapture the printed media ejected from the printer unit 2. The leadingedge of the printed media is captured upon contacting the stop member 58of the lower output tray 52 following exiting the main body 3. Theamount by which the media output assembly 5 is extended is dependantupon the size of the media being printed. For example, if the printmedia is of a length such as that shown in FIG. 12, such as A4 sizedmedia, then the print media assembly 5 may need to be fully extended inorder to capture and retain the printed media.

As will be appreciated, the media output assembly 5 is removable fromthe printer unit 2 and is only employed when the printer unit 2 is usedsolely as an inkjet printer and not as part of the image processingapparatus 1. The manner in which the image processing apparatus isconfigured will be described in more detail below.

As is shown in FIG. 13, and as mentioned previously, access to theinternal cavity 12 of the main body 3 is possible by pivoting the lid 21of the cover 11 backwards. The internal cavity 12 receives the printengine 70 as well as the paper handling mechanisms in the form of apicker mechanism 60.

As alluded to previously, the purpose of the picker mechanism 60 is toseparate and transport single sheets of print media from the media inputassembly 4 for delivery to the print engine 70 for printing. As theprinter unit 2 can operate at speeds up to, and in excess of, 60 ppm thepicker unit is configured to separate and transport sheets of printmedia to the print engine 70 at a rate suitable for achieving theseprinting speeds. As such, the picker mechanism 60 consists of a pickerroller 61 which is disposed at the end of an arm 62 that extends fromthe picker body 63. The picker body 63 contains a motor 64 which iscontrolled by the control electronics 72 of the printer unit 2. Thepicker body 63 is pivotally mounted to the lower frame unit 6 and isspring loaded such that the picker roller 61 is urged towards theworking surface 35 of the tray portion 32.

In the absence of print media 34 in the tray portion 32, the pickerroller 61 is urged into contact with the idler roller 39 provided on theworking surface 35 of the tray portion 32. In order to load print mediainto the tray portion 32, media 34 is inserted into the tray portion 32and contacts a guide element 66 provided over the picker roller 61. Thiscontact causes the picker mechanism 60 to pivot away from the workingsurface 35 of the tray portion 32, and allows the print media to bereceived between the picker roller 61 and the idler roller 39, with theleading edge of the print media 34 supported on the media supportsurface 36. This arrangement is shown in FIG. 14.

The surface of the picker roller 61 is provided with a gripping means,which may be in the form of a rubber coating or other similar typecoating or surface treatment which facilitates gripping of the roller toa sheet of print media 34. As the picker roller 61 rotates, under actionof the motor 64, the sheet of print media in contact with the pickerroller 61 is caused to slide along the raised strips 40 for delivery tothe print engine 70. The outermost sheet is separated from the othersheets present in the tray portion 32 due to the pad 41 provided on thesurface of the strip 40 adjacent the picker mechanism 60. In thisregard, any sheets of media that move with the outermost sheet willexperience a friction force as they slide over the pad 41 which isgreater than the friction force causing the motion, and as such only theoutermost sheet will be delivered to the print engine 70.

It will be appreciated that the picker mechanism 60 is employed toseparate the print media 34 and to transport individual sheets of printmedia, at relatively high speeds, to the print engine 70 for printingand as such the type of picker mechanism 60 employed to perform thisfunction could vary and still fall within the scope of the presentinvention.

The print engine assembly 70 employed by the present invention isgenerally comprised of two parts: a cradle unit 71 and a cartridge unit80. In this arrangement, the cartridge unit 80 is arranged to bereceived within the cradle unit 71.

As shown in FIG. 14, the cartridge unit 80 has a body that houses aprinthead integrated circuit 81 for printing on a sheet of print media34 as it passes thereby. The body of the cartridge unit 80 also housesink handling and storage reservoirs 82 for storing and delivering ink tothe printhead integrated circuit 81. The printhead integrated circuit 81is a pagewidth printhead integrated circuit that is disposed along theoutside of the body of the cartridge in a region below the ink handlingand storage reservoirs 82 to extend the width of the media 34 beingprinted. As opposed to conventional printer units, the printheadintegrated circuit 81 of the present invention is fixed in positionduring operation and does not scan or traverse across the print media.As such the print engine of the present invention is able to achieve farhigher printing speeds than is currently possible with conventionalprinter systems. The manner in which the printhead integrated circuit 81is configured and controlled will be discussed in more detail later inthe description.

Power and data signals are provided from the control electronics 72located on the cradle unit 71 to control the operation of the printheadintegrated circuit 81. The control electronics 72 includes thepreviously described SoPEC device and signals are transmitted from thecontrol electronics 72 to the cartridge unit 80 via data and powerconnectors (not shown) provided on the periphery of the body of thecartridge unit 80. Upon inserting the cartridge unit 80 into the cradleunit 71, the data and power connectors mate with corresponding data andpower connectors provided on the cradle unit 71, thereby facilitatingpower and data communication between the units 71, 80.

The ink handling and storage reservoirs 82 are in the form of aplurality of polyethylene membrane pockets that separately storedifferent types of inks and printing fluids for printing. For example,the cartridge unit 80 may be provided with six separate polyethylenemembrane reservoirs for storing cyan, magenta, yellow and black ink forfull colour printing as well as infra-red ink for specific printingapplications and an ink fixative to aid in the setting of the ink. Eachor the reservoirs 82 may be in fluid communication with a correspondinginlet provided in a refill port (not shown) formed on the periphery ofthe body of the cartridge unit 80. As such, the reservoirs 82 are ableto be individually refilled by bringing an ink refill dispenser intocontact with the refill port and delivering ink under pressure into thereservoirs 82. As mentioned previously, the ink refill dispenser may beequipped with a QA chip which is read by a corresponding reader providedon the body of the cartridge unit 80. The associated data is thentransmitted to the SoPEC device provided in the control electronics 72of the cradle unit 71 to ensure the integrity and quality of the refillfluid. To facilitate refilling, the polyethylene membrane reservoirs 82are configured such that as they fill they expand to accommodate thefluid and as the ink/fluid is consumed during the printing process thereservoir collapses.

Ink and printing fluids stored within the reservoirs 82 are delivered tothe printhead integrated circuit 81 via a series of conduits 79 arrangedto carry a specific fluid, such as a particular colour ink or fixative,and to allow the fluid to be distributed to the correct ink deliverynozzle provided along the length of the printhead integrated circuit 81.The manner in which this is achieved and the general construction of thecartridge unit 80 has been described in the present Applicant's UnitedStates patent applications Filing Docket Nos. RRA01US to RRA33US, thedisclosures of which are all incorporated herein by reference. The aboveapplications have been identified by their filing docket number, whichwill be substituted with the corresponding application number, onceassigned.

As mentioned above, the printhead integrated circuit 81 of the cartridgeunit 80 is a pagewidth printhead integrated circuit which is configuredto extend a width of around 22.4 cm (8.8 inches) to accommodate printmedia of a variable width up to around 21.6 cm, which is equivalent tomedia having the width of standard A4 or US letter form. It is alsoenvisaged however, that the pagewidth printhead integrated circuit 81may also be fabricated to have a greater or lesser width, dependantgreatly upon the application of the printer unit 2 and the type of printmedia used. In order to achieve the desired width, the printheadintegrated circuit 81 may be made up of a one or more adjacently mountedintegrated circuits with each integrated circuit having a plurality ofink delivery nozzles provided thereon.

An example of a type of printhead nozzle arrangement suitable for thepresent invention, comprising a nozzle and corresponding actuator, willnow be described with reference to FIGS. 16 to 25. FIG. 25 shows anarray of the nozzle arrangements 801 formed on a silicon substrate 8015.Each of the nozzle arrangements 801 are identical, however groups ofnozzle arrangements 801 are arranged to be fed with different coloredinks or fixative. In this regard, the nozzle arrangements are arrangedin rows and are staggered with respect to each other, allowing closerspacing of ink dots during printing than would be possible with a singlerow of nozzles. Such an arrangement makes it possible to provide thedensity of nozzles as described above. The multiple rows also allow forredundancy (if desired), thereby allowing for a predetermined failurerate per nozzle.

Each nozzle arrangement 801 is the product of an integrated circuitfabrication technique. In particular, the nozzle arrangement 801 definesa micro-electromechanical system (MEMS).

For clarity and ease of description, the construction and operation of asingle nozzle arrangement 801 will be described with reference to FIGS.16 to 24.

The inkjet printhead chip 81 includes a silicon wafer substrate 8015having 0.35 Micron 1 P4M 12 volt CMOS microprocessing electronics ispositioned thereon.

A silicon dioxide (or alternatively glass) layer 8017 is positioned onthe substrate 8015. The silicon dioxide layer 8017 defines CMOSdielectric layers. CMOS top-level metal defines a pair of alignedaluminium electrode contact layers 8030 positioned on the silicondioxide layer 8017. Both the silicon wafer substrate 8015 and thesilicon dioxide layer 8017 are etched to define an ink inlet channel8014 having a generally circular cross section (in plan). An aluminiumdiffusion barrier 8028 of CMOS metal 1, CMOS metal 2/3 and CMOS toplevel metal is positioned in the silicon dioxide layer 8017 about theink inlet channel 8014. The diffusion barrier 8028 serves to inhibit thediffusion of hydroxyl ions through CMOS oxide layers of the driveelectronics layer 8017.

A passivation layer in the form of a layer of silicon nitride 8031 ispositioned over the aluminium contact layers 8030 and the silicondioxide layer 8017. Each portion of the passivation layer 8031positioned over the contact layers 8030 has an opening 8032 definedtherein to provide access to the contacts 8030.

The nozzle arrangement 801 includes a nozzle chamber 8029 defined by anannular nozzle wall 8033, which terminates at an upper end in a nozzleroof 8034 and a radially inner nozzle rim 804 that is circular in plan.The ink inlet channel 8014 is in fluid communication with the nozzlechamber 8029. At a lower end of the nozzle wall, there is disposed amoving rim 8010, that includes a moving seal lip 8040. An encirclingwall 8038 surrounds the movable nozzle, and includes a stationary seallip 8039 that, when the nozzle is at rest as shown in FIG. 18, isadjacent the moving rim 8010. A fluidic seal 8011 is formed due to thesurface tension of ink trapped between the stationary seal lip 8039 andthe moving seal lip 8040. This prevents leakage of ink from the chamberwhilst providing a low resistance coupling between the encircling wall8038 and the nozzle wall 8033.

As best shown in FIG. 23, a plurality of radially extending recesses8035 is defined in the roof 8034 about the nozzle rim 804. The recesses8035 serve to contain radial ink flow as a result of ink escaping pastthe nozzle rim 804.

The nozzle wall 8033 forms part of a lever arrangement that is mountedto a carrier 8036 having a generally U-shaped profile with a base 8037attached to the layer 8031 of silicon nitride.

The lever arrangement also includes a lever arm 8018 that extends fromthe nozzle walls and incorporates a lateral stiffening beam 8022. Thelever arm 8018 is attached to a pair of passive beams 806, formed fromtitanium nitride (TiN) and positioned on either side of the nozzlearrangement, as best shown in FIGS. 19 and 24. The other ends of thepassive beams 806 are attached to the carrier 8036.

The lever arm 8018 is also attached to an actuator beam 807, which isformed from TiN. It will be noted that this attachment to the actuatorbeam is made at a point a small but critical distance higher than theattachments to the passive beam 806.

As best shown in FIGS. 16 and 22, the actuator beam 807 is substantiallyU-shaped in plan, defining a current path between the electrode 809 andan opposite electrode 8041. Each of the electrodes 809 and 8041 areelectrically connected to respective points in the contact layer 8030.As well as being electrically coupled via the contacts 809, the actuatorbeam is also mechanically anchored to anchor 808. The anchor 808 isconfigured to constrain motion of the actuator beam 807 to the left ofFIGS. 16 to 18 when the nozzle arrangement is in operation.

The TiN in the actuator beam 807 is conductive, but has a high enoughelectrical resistance that it undergoes self-heating when a current ispassed between the electrodes 809 and 8041. No current flows through thepassive beams 806, so they do not expand.

In use, the device at rest is filled with ink 8013 that defines ameniscus 803 under the influence of surface tension. The ink is retainedin the chamber 8029 by the meniscus, and will not generally leak out inthe absence of some other physical influence.

As shown in FIG. 17, to fire ink from the nozzle, a current is passedbetween the contacts 809 and 8041, passing through the actuator beam807. The self-heating of the beam 807 due to its resistance causes thebeam to expand. The dimensions and design of the actuator beam 807 meanthat the majority of the expansion in a horizontal direction withrespect to FIGS. 16 to 18. The expansion is constrained to the left bythe anchor 808, so the end of the actuator beam 807 adjacent the leverarm 8018 is impelled to the right.

The relative horizontal inflexibility of the passive beams 806 preventsthem from allowing much horizontal movement the lever arm 8018. However,the relative displacement of the attachment points of the passive beamsand actuator beam respectively to the lever arm causes a twistingmovement that causes the lever arm 8018 to move generally downwards. Themovement is effectively a pivoting or hinging motion. However, theabsence of a true pivot point means that the rotation is about a pivotregion defined by bending of the passive beams 806.

The downward movement (and slight rotation) of the lever arm 8018 isamplified by the distance of the nozzle wall 8033 from the passive beams806. The downward movement of the nozzle walls and roof causes apressure increase within the chamber 29, causing the meniscus to bulgeas shown in FIG. 17. It will be noted that the surface tension of theink means the fluid seal 11 is stretched by this motion without allowingink to leak out.

As shown in FIG. 18, at the appropriate time, the drive current isstopped and the actuator beam 807 quickly cools and contracts. Thecontraction causes the lever arm to commence its return to the quiescentposition, which in turn causes a reduction in pressure in the chamber8029. The interplay of the momentum of the bulging ink and its inherentsurface tension, and the negative pressure caused by the upward movementof the nozzle chamber 8029 causes thinning, and ultimately snapping, ofthe bulging meniscus to define an ink drop 802 that continues upwardsuntil it contacts adjacent print media.

Immediately after the drop 802 detaches, meniscus 803 forms the concaveshape shown in FIG. 18. Surface tension causes the pressure in thechamber 8029 to remain relatively low until ink has been sucked upwardsthrough the inlet 8014, which returns the nozzle arrangement and the inkto the quiescent situation shown in FIG. 16.

The printhead integrated circuit 81 may be arranged to have between 5000to 100,000 of the above described nozzles arranged along its surface,depending upon the length of the printhead integrated circuit 81 and thedesired printing properties required. For example, for narrow media itmay be possible to only require 5000 nozzles arranged along the surfaceof the printhead to achieve a desired printing result, whereas for widermedia a minimum of 10,000, 20,000 or 50,000 nozzles may need to beprovided along the length of the printhead to achieve the desiredprinting result. For full colour photo quality images on A4 or US lettersized media at or around 1600 dpi, the printhead integrated circuit 81may have 13824 nozzles per color. Therefore, in the case where theprinthead integrated circuit 81 is capable of printing in 4 colours (C,M, Y, K), the printhead integrated circuit 81 may have around 53396nozzles disposed along the surface thereof. Further, in a case where theprinthead integrated circuit 81 is capable of printing 6 printing fluids(C, M, Y, K, IR and a fixative) this may result in 82944 nozzles beingprovided on the surface of the printhead integrated circuit 81. In allsuch arrangements, the electronics supporting each nozzle is the same.

The manner in which the individual nozzle arrangements 101 arecontrolled within the printhead integrated circuit 81 will now bedescribed with reference to FIGS. 26-29.

FIG. 26 shows an overview of the printhead integrated circuit 81 and itsconnections to the SoPEC device provided within the control electronics72 of the printer unit 2. As discussed above, printhead integratedcircuit 81 includes a nozzle core array 401 containing the repeatedlogic to fire each nozzle, and nozzle control logic 402 to generate thetiming signals to fire the nozzles. The nozzle control logic 402receives data from the SoPEC device via a high-speed link.

The nozzle control logic 402 is configured to send serial data to thenozzle array core for printing, via a link 407, which may be in the formof an electrical connector. Status and other operational informationabout the nozzle array core 401 is communicated back to the nozzlecontrol logic 402 via another link 408, which may be also provided onthe electrical connector.

The nozzle array core 401 is shown in more detail in FIGS. 27 and 28. InFIG. 27, it will be seen that the nozzle array core 401 comprises anarray of nozzle columns 501. The array includes a fire/select shiftregister 502 and up to 6 color channels, each of which is represented bya corresponding dot shift register 503.

As shown in FIG. 28, the fire/select shift register 502 includes forwardpath fire shift register 600, a reverse path fire shift register 601 anda select shift register 602. Each dot shift register 503 includes an odddot shift register 603 and an even dot shift register 604. The odd andeven dot shift registers 603 and 604 are connected at one end such thatdata is clocked through the odd shift register 603 in one direction,then through the even shift register 604 in the reverse direction. Theoutput of all but the final even dot shift register is fed to one inputof a multiplexer 605. This input of the multiplexer is selected by asignal (corescan) during post-production testing. In normal operation,the corescan signal selects dot data input Dot[x] supplied to the otherinput of the multiplexer 605. This causes Dot[x] for each color to besupplied to the respective dot shift registers 503.

A single column N will now be described with reference to FIG. 28. Inthe embodiment shown, the column N includes 12 data values, comprisingan odd data value 606 and an even data value 607 for each of the six dotshift registers. Column N also includes an odd fire value 608 from theforward fire shift register 600 and an even fire value 609 from thereverse fire shift register 601, which are supplied as inputs to amultiplexer 610. The output of the multiplexer 610 is controlled by theselect value 611 in the select shift register 602. When the select valueis zero, the odd fire value is output, and when the select value is one,the even fire value is output.

Each of the odd and even data values 606 and 607 is provided as an inputto corresponding odd and even dot latches 612 and 613 respectively.

Each dot latch and its associated data value form a unit cell, such asunit cell 614. A unit cell is shown in more detail in FIG. 29. The dotlatch 612 is a D-type flip-flop that accepts the output of the datavalue 606, which is held by a D-type flip-flop 614 forming an element ofthe odd dot shift register 603. The data input to the flip-flop 614 isprovided from the output of a previous element in the odd dot shiftregister (unless the element under consideration is the first element inthe shift register, in which case its input is the Dot[x] value). Datais clocked from the output of flip-flop 614 into latch 612 upon receiptof a negative pulse provided on LsyncL.

The output of latch 612 is provided as one of the inputs to athree-input AND gate 615. Other inputs to the AND gate 615 are the Frsignal (from the output of multiplexer 610) and a pulse profile signalPr. The firing time of a nozzle is controlled by the pulse profilesignal Pr, and can be, for example, lengthened to take into account alow voltage condition that arises due to low power supply (in aremovable power supply embodiment). This is to ensure that a relativelyconsistent amount of ink is efficiently ejected from each nozzle as itis fired. In the embodiment described, the profile signal Pr is the samefor each dot shift register, which provides a balance betweencomplexity, cost and performance. However, in other embodiments, the Prsignal can be applied globally (ie, is the same for all nozzles), or canbe individually tailored to each unit cell or even to each nozzle.

Once the data is loaded into the latch 612, the fire enable Fr and pulseprofile Pr signals are applied to the AND gate 615, combining to thetrigger the nozzle to eject a dot of ink for each latch 612 thatcontains a logic 1.

The signals for each nozzle channel are summarized in the followingtable:

Name Direction Description D Input Input dot pattern to shift registerbit Q Output Output dot pattern from shift register bit SrClk InputShift register clock in - d is captured on rising edge of this clockLsyncL Input Fire enable - needs to be asserted for nozzle to fire PrInput Profile - needs to be asserted for nozzle to fire

As shown in FIG. 29, the fire signals Fr are routed on a diagonal, toenable firing of one color in the current column, the next color in thefollowing column, and so on. This averages the current demand byspreading it over 6 columns in time-delayed fashion.

The dot latches and the latches forming the various shift registers arefully static in this embodiment, and are CMOS-based. The design andconstruction of latches is well known to those skilled in the art ofintegrated circuit engineering and design, and so will not be describedin detail in this document.

The nozzle speed may be as much as 20 kHz for the printer unit 2 capableof printing at about 60 ppm, and even more for higher speeds. It shouldbe appreciated that all references to printing speeds and ppm, willrefer to pages printed with full process colour images (not spot colour)and requiring at least 80% image coverage of the page. Hence a printingspeed of 60 ppm refers to the printing of a 60 page of media per minutewhereby the pages are printed with full process colour images that coverat least 80% of each page. As such, all comparisons with existingprinter units are based upon this printing requirement. At this range ofnozzle speeds the amount of ink than can be ejected by the entireprinthead 81 is at least 50 million drops per second. However, as thenumber of nozzles is increased to provide for higher-speed andhigher-quality printing at least 100 million drops per second,preferably at least 300 million drops per second, and more preferably atleast 1 billion drops per second may be delivered. Consequently, inorder to accommodate printing at these speeds, the control electronics72, must be able to determine whether a nozzle is to eject a drop of inkat an equivalent rate. In this regard, in some instances the controlelectronics must be able to determine whether a nozzle ejects a drop ofink at a rate of at least 50 million determinations per second. This mayincrease to at least 100 million determinations per second or at least300 million determinations per second, and in many cases at least 1billion determinations per second for the higher-speed, higher-qualityprinting applications.

For the printer unit 2 of the present invention, the above-describedranges of the number of nozzles provided on the printhead chip 81together with the nozzle firing speeds print speeds results in an areaprint speed of at least 50 cm² per second, and depending on the printingspeed, at least 100 cm² per second, preferably at least 200 cm² persecond, and more preferably at least 500 cm² per second at thehigher-speeds. Such an arrangement provides a printer unit 100 that iscapable of printing an area of media at speeds not previously attainablewith conventional printer units

As mentioned previously, the above described nozzle arrangements areformed in the printhead integrated circuit 81 of the cartridge unit 80,which forms one part of the print engine 70. The cartridge unit 80relies upon data and power to be transferred from the controlelectronics 72 of the cradle unit 71 in order to function and alsorelies upon the cradle unit 71 to support the printhead integratedcircuit 81 in a printing position and deliver the print media past theprinthead integrated circuit 81 for printing.

In this regard, the cradle unit 71 forms the second part of the printengine 70 and is retained within the internal cavity 12 of the main body3 via mountings (not shown) provided on the upper and lower frame units7, 6. In this position, as shown in FIGS. 13 and 14, the cradle unit 71is able to receive data from external data sources via a connectorelement 73 which is in electrical communication with the data connectorsockets 17 provided on the rear 9 of the main body 3. The connectorelement 73 is preferably a flexible printed circuit board (PCB),positioned to align with a corresponding connector provided on thecradle unit 71. Similarly, power is supplied to the cradle unit 71 fromthe power supply unit 15 by way of power contacts (not shown) whichextend into the internal cavity 12. The cradle unit 71 is provided witha suitable connector element (not shown) which connects with the powercontacts 74 to deliver power to the cradle unit 71.

As shown more clearly in FIG. 14, the cradle unit 71 is shaped toreceive the cartridge unit 80 such that when mated together both unitsform the print engine assembly 70. In this arrangement, data and poweris able to be transferred between the units 71, 80 as previouslydescribed, thereby allowing the nozzles of the printhead integratedcircuit 81 to be controlled in the manner previously described.

The body of the cradle unit 71 comprises a drive motor 75, a driveroller 76 and a pinch roller 77 for transporting paper through the printengine 70, a printhead maintenance unit 78 for providing capping andother forms of maintenance to the printhead integrated circuit 81, andcontrol electronics 72 which includes the SoPEC device for controllingthe overall operation of the printer unit 2. The body of the cradle unitalso houses a media exit mechanism in the form of an exit roller 86 andidler wheels 87 to aid in delivering the printed media from the printengine 70 for collection.

The drive motor 75 is a standard brushless DC motor having bidirectionalcapabilities. The drive motor 75 is gearingly engaged with the driveroller 76 to provide driving motion to the drive roller 76 to controldelivery of print media past the printhead integrated circuit 81. Thespeed at which the drive roller 76 is driven by the motor 75 iscontrolled by the control electronics 72 to ensure that the paper isdelivered past the printhead 81 at the desired rate, which is typicallyup to, and in excess of, 60 ppm. The drive roller 76 engages with apinch roller 77 and together the rollers 76, 77 cooperate to capture theprint media supplied by the picker mechanism 60 and advance the printmedia past the printhead integrated circuit 81.

The cradle unit 71 is also provided with a printhead maintenance unit 78which is also gearingly engaged to the drive motor 75. The printheadmaintenance unit 78 includes a capping element that is adapted to bemoved into position to cap the printhead integrated circuit 81 of thecartridge unit 80. In such instances, upon determination of an idlestate of the printer unit 2, the control electronics 72 initiatesengagement of the printhead maintenance unit 78 with the drive motor 75to move the printhead maintenance unit 78 into capping engagement withthe printhead integrated circuit 81. The capping engagement essentiallyforms a perimeter seal around the ink delivery nozzles of the printheadintegrated circuit 81, thereby reducing the evaporation of moisture fromthe ink present in the ink delivery nozzles, and preventing ink fromdrying and clogging the nozzles. Similarly, upon determination of theonset of printing, the control electronics 72 initiates uncapping of theprinthead integrated circuit 81 thereby allowing the printheadmaintenance unit 78 to return to an uncapped position such as that shownin FIG. 16. The printhead maintenance 78 unit may also perform otherfeatures such as wiping or blotting of the printhead 81, as necessary.

The paper exit mechanism 85 is positioned on the inside of the cradleunit 70 downstream of the printhead integrated circuit 81, and consistsof an exit roller 86 and a plurality of idler wheels 87. The exit roller86 is provided by an elongate shaft that extends across the cradle unit.The exit roller 86 may have a plurality of gripping elements equispacedalong the length of the shaft to aid in capturing the media for deliveryto the media output assembly 5. The exit roller 86 is driven by thedrive motor 75 of the cradle unit 71 via appropriately arranged drivegears, and the control electronics 72 of the cradle unit 71 is able tocontrol the operation of the paper exit mechanism 85 to ensure that itis initiated at an appropriate time and speed to correspond with thespeed and timing of the drive roller 76 of the cradle unit 71.

The idler wheels 87 of the paper exit mechanism 85 act in cooperationwith the exit roller 86 to capture and deliver the printed media to themedia output assembly 5. The idler wheels 87 are flexibly connected tothe inside surface of the cradle unit 71 and are arranged to be inrotational contact with the exit roller 86. As shown in FIG. 14, theidler wheels 87 are in the form of star wheels 91 which rotate upon thesurface of the exit roller 86 and capture the media therebetween, suchthat the printed media can be delivered under action of the exit roller86 to the media output assembly 5. This arrangement assists incontrolling the removal of the sheet of printed media from the printengine 70 following printing.

It should be appreciated that whilst the paper exit mechanism 85 isshown as being contained within the cradle unit 71, the paper exitmechanism could also be provided remote from the cradle unit, andattached to the main body 3 of the printer unit. Further, whilst thepaper exit mechanism 85 is shown as having star wheels 91, other typesof idler rollers could also be employed as would be apparent to a personskilled in the art and still fall within the scope of the presentinvention.

As shown in FIG. 16, the body of the cradle unit 71 has an inlet 67provided upstream of the printhead integrated circuit 81, adjacent thepicker mechanism 60. The inlet 67 receives a leading edge of the printmedia delivered by the picker mechanism 60 and includes guide members 69that assist in directing the leading edge of the print media towards thedrive and pinch rollers 76, 77.

An outlet 68 is provided in the body of the cradle unit 71 downstream ofthe printhead integrated circuit 81 paper exit mechanism to provide apath for the print media to exit the print engine 70. Following printingby the printhead integrated circuit 81, the leading edge of the printedmedia exits the print engine 70 via the outlet 68 under the action ofthe paper exit mechanism 85.

In the described arrangement, the print engine 70 is located within theinternal cavity 12 of the main body 3 to allow for a simple print mediatransport path from the media input assembly 4, through the print engine70, and into the media output assembly 5.

As shown in FIG. 14, in order to simplify the path for the print mediaas it progresses through the printer unit 2, the print engine 70 isangularly disposed within the internal cavity 12 of the main body 3. Theangular disposition of the print engine 70 results in the printheadintegrated circuit 81 being angularly disposed, thus providing anangularly disposed printing zone, which aids in providing a shallow pathfor the print media as it passes from the media input assembly 4 throughthe printing zone to the media output assembly 5. Such a simplified andshallow print media path allows media of varying thicknesses and types,namely paper up to around 300 gsm, to be printed by the printer unit 2,such a variability in media handling capabilities which is typicallylacking in conventional desktop printer units. This arrangement reducesthe likelihood of the print media becoming jammed along its path andrequiring constant monitoring and rectification and in some instancesrepair or replacement, should the media contact the printhead integratedcircuit 81.

The angle in which the print engine 70 is disposed, and therefore theangle of inclination of the printhead integrated circuit 81, is largelydependant upon the angle with which the print media 10 is supplied tothe printer unit 2, in particular the angle of inclination of the mediainput assembly 4. As shown in FIG. 16, the print media input assembly 4has an angle of inclination of around 120°, the angle of inclinationbeing measured in a counterclockwise direction from the positive x-axis,with a horizontal surface having an angle of inclination of 0°. Theangle of inclination of the print media input assembly could vary frombetween 90°-160°. In the arrangement shown in FIG. 16, the print engine70, and subsequently the printhead integrated circuit 81, has an angleof inclination of around 145°, which is greater than the angle ofinclination of the print media input assembly 4. Therefore, in order toprovide a shallow print media path that is capable of handling printmedia of varying weights and thicknesses, the printhead integratedcircuit 81 is arranged to have an angle of inclination that is greaterthan the angle of inclination of the print media input assembly.

Image Reading Unit

The image reading unit 701 of the image processing apparatus 1 is shownin exploded view in FIG. 30. As can be appreciated, the image readingunit 701 resembles a traditional flat bed scanner unit that employs atraditional reciprocating pagewidth image reader 702 to scan an imagefrom a source. The image reader 702 is in the form of a scanner headassembly as would be understood by a person skilled in the art.

The image reading unit 701 generally consists of base 703, a frame 710and a lid 720. The base 703 contains the various operational elements ofthe image reading unit 701. The image reader 702 is located within oneend of the base 703 and is supported on a central shaft 704 along whichthe image reader 702 travels as it reads the image. A motor 707 ismounted to the base 703 to drive a belt assembly 705 which is arrangedin a parallel relationship with the central shaft 704. The belt assembly705 is connected to the image reader 702 and causes it to move along thecentral shaft 704 under action of the motor 707, thereby allowing theimage reader 702 to traverse the base 703 to scan an image. A belttensioning system 706 is employed at the end of the belt assembly 705remote from the motor 707 to ensure that the belt is of a sufficienttension to provide consistent movement of the image reader 702 along thelength of the scanner unit 701.

The image reader 702 and the motor 707 are controlled by a controller708 provided on a PCB assembly (partially obscured). As the image reader702 traverses the length of the image reading unit 701, it is connectedto the controller 708 via a flex PCB 709 which is shown in a foldedarrangement. In this regard, as the image reader 702 moves along thelength of the base 703 the flex PCB 709 extends from the foldedarrangement to ensure that the image reader 702 is in constantcommunication with the controller 708 to enable data and power to betransferred between the two elements. In this arrangement, imageinformation associated with the image being read is collected by theimage reader 702 and recorded or stored within the controller 708 forlater processing.

The frame 710 is arranged to fit over the base 703 and be maintained inengagement via lugs 711 provided on the frame 710 which mate withcorresponding recesses 712 provided on the base 703. A flat glass panel713 is sandwiched between the base 703 and the frame 710. The glasspanel 713 is intended to support a sheet of printed media and presentthe media for reading by the image reader 702 in the manner as describedabove.

At the rear of the frame 710 is provided a seat portion 714. The seatportion 714 forms an open receptacle having a floor portion 715 and twosets of locating elements 716 extending upwardly from the floor portion715. The locating elements 716 each consist of a central cylindricalelement 717 surrounded by four raised locating tabs 718. A spacerelement 719 also extends from the floor portion 715 of the seat portion.The purpose of the locating elements 716 and the spacer element 719 isto receive the printer unit 2 in a manner which will be described inmore detail below.

The lid 720 is arranged to be cover the glass panel 713 and is pivotallyconnected to the frame 710 to pivot between a closed position, wherebythe lid covers the glass panel 713, and an open position, whereby thelid 720 is moved away from the glass panel 713. A pad 721 is provided onthe inner surface of the lid 720 to assist in maintaining items to beread in position on the glass panel 713. In this regard, when the lid720 is in a closed position, and an item to be read is placed on theglass panel 713, the pad 721 contacts the item and maintains the item inplace on the surface of the glass panel 713.

The outer surface of the lid 720 is provided with a number of ridges 722extending the length thereof and generally defines a flat surface thatis used to collect printed media from the printer unit 2 in a mannerwhich will be described in more detail below. An end stop 723 isprovided on the outer surface of the lid 720 to aid in collection ofprinted media from the printer unit 2.

The lid 720 is attached to the frame 710 by way of a pair of pins (notshown) provided on two inner corners of the lid 720. The pins arereceived within two shaped recesses 724 provided on the outer surface ofthe frame 710 and this arrangement allows the lid 720 to pivot about thepins between an open and a closed position. A region of the frame 710immediately adjacent the edge upon which the lid 720 is attached isprovided with a grooved region 725 which assists the lid 720 in pivotingabout the frame 710.

Whilst the image reading unit 710 described above and shown in FIG. 30is a flat bed scanner employing a reciprocating pagewidth head assembly,it will be appreciated that the scanner unit could be any form ofcommercially available scanner units and as such the present inventionis not limited to the type of scanner unit employed.

Multi-Purpose Image Processing Apparatus

In order to form the multi-purpose image processing apparatus 1 as shownin FIG. 1, both the printer unit 2 and the image reading unit 701 areconstructed in a manner which allows simple assembly of both unitstogether.

As alluded to previously, the seat portion 714 of the image reading unit701 is configured to receive the base 8 of the printer unit 2, and thelocating elements 716 act to secure the printer unit 2 in place.

Referring to FIG. 11, in order to assemble the printer unit 2 and theimage reading unit 701 together to form the multi-purpose imageprocessing apparatus 1, the media output assembly 5 is firstly removedfrom the base 8 of the printer unit 2. As the media output assembly 5 isslidingly received within a recessed portion formed in the base 8 of theprinter unit 2, it can merely be removed from the base prior to assemblyto the image reading unit 701. Two receiving regions 59 are formed onthe surface of the base 8 and are in the form of a central circularrecess, with four substantially rectangular recesses disposed about thecentral circular recess.

The printer unit 2 can then be placed within the seat portion 714 of theimage reading unit 701, with the seat portion 714 shaped to conform tothe general shape of the base 8 of the printer unit 2. Upon receival ofthe printer unit 2 within the seat portion 714, the receiving regions 59formed on the base 8 of the printer unit 2 receive the locating elements716 provided on the seat portion 714. In this regard, the raised tabs718 are received within the corresponding substantially rectangularrecesses of the receiving regions 59 and the cylindrical element 717 isreceived within the corresponding central circular recess of thereceiving regions 59, thereby releasably securing the printer unit 2 tothe image reading unit 701 in a nested arrangement. The spacer element719 of the seat portion 714 acts against the base 8 of the printer unit2 to provide further support of the printer unit 2 within the seatportion 714. The underside of the assembled arrangement is shown in FIG.31.

In this arrangement, the controller 708 of the image reading unit 701can be directly connected to the control system 72 of the printer unit 2via appropriate electrical connections (not shown). Such electricalconnections can be provided within the cylindrical element 717 to extendinto the internal cavity 12 of the printer unit 2 to enable datatransfer between the controller 708 of the image reading unit 701 andthe control system 72 of the printer unit 2. Further, a power connectioncan be provided from the power supply unit 15 to provide operationalpower to the image reading unit 701 in a similar manner. In this regard,it is possible to operate the image reading unit 701 to read an imagefrom a printed document and to process and send the image to the printerunit 2 for immediate printing. Further, the control system 72 can sendthe collected image data to a remote computer system or the like via thedata connection sockets or WIFI cards provide on the printer unit 2. Theimage reading unit 701 is operated via the user display unit 26 mountedon the printer unit 2, such that a user can enter commands via the userdisplay unit 26 to control the operation of the image reading unit 701.

In the assembled arrangement, as shown in FIGS. 32-35, the lid 720 ofthe image reading unit 701 extends from the printer unit 2 to collectprinted media ejected therefrom, in the absence of the media outputassembly 5. In this regard, the media 34 exits the printer unit 2 underaction of the media exit mechanism 85 onto the lid 720 of the imagereading unit 701. The end stop 723 collects the leading edge of themedia 34 thereby retaining the printed media for collection.

To facilitate the reading and recording of an image from a documentusing the image reading unit 701, the lid 720 is raised to enable thedocument to be placed on the surface of the glass panel 713. Thisarrangement is shown in FIG. 36. In this regard, the image reading unit701 is constructed such that it can be readily operated in aconventional manner independently of the printer unit 2.

While the present invention has been illustrated and described withreference to exemplary embodiments thereof, various modifications willbe apparent to and might readily be made by those skilled in the artwithout departing from the scope and spirit of the present invention.Accordingly, it is not intended that the scope of the claims appendedhereto be limited to the description as set forth herein, but, rather,that the claims be broadly construed.

1. A printer unit comprising: a body having a media input assembly forsupporting media to be printed, and securing means for releasableengagement with complementary securing means on an image reader unit;and a print engine having a printhead and a control system forcontrolling operation of the printhead, wherein the body is shaped fornesting with the image reader unit such that the securing means arepositioned for releasable engagement with the complementary securingmeans; and the body is configured so that the nested image reader unitextends outwardly from the print engine such that printed media iscollected on a surface of the image reader unit.
 2. A printer unitaccording to claim 1, wherein the print engine comprises a media exitmechanism for ejecting said printed media following printing.
 3. Aprinter unit according to claim 2, wherein the media exit mechanism isarranged to cooperate with a stop member arranged on said surface of theimage reader unit so that a leading edge of the ejected printed media iscaptured by said surface.
 4. A printer unit according to claim 1,wherein the printhead is a pagewidth inkjet printhead having a pluralityof ink ejection nozzles for ejecting ink onto a surface of the media asthe media is transported therepast.
 5. A printer unit according to claim4, wherein said printhead is incorporated in a cartridge which isremovably received by the print engine.
 6. A printer unit according toclaim 5, wherein the cartridge comprises at least one ink storagereservoir for storing ink for ejection by said ink ejection nozzles ofsaid printhead.
 7. A printer unit according to claim 5, wherein theprint engine comprises a cradle and the cradle is configured to receivethe cartridge.
 8. A printer unit according to claim 7, wherein thecradle incorporates a media input mechanism for transporting input mediafrom the media input assembly to said printhead.
 9. A printer unitaccording to claim 8, wherein the control system controls the operationof the media input mechanism.
 10. A printer unit according to claim 9,wherein the cradle incorporates the control system.
 11. A printer unitaccording to claim 1, wherein the control system controls operation ofthe nested image reader unit.